1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
|
/*
* Copyright (c) 2007 Sun Microsystems, Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* - Redistribution of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistribution in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* Neither the name of Sun Microsystems, Inc. or the names of
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
* INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
* PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
* MICROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR
* ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
* DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR
* ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR
* DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
* DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
* ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
* SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
*
* You acknowledge that this software is not designed or intended for use
* in the design, construction, operation or maintenance of any nuclear
* facility.
*
*/
package net.java.joglutils.msg.impl;
import net.java.joglutils.msg.math.*;
/** Intersection of ray with triangle. Computes parameteric t along
with barycentric coordinates (u, v) indicating weight of vert1 and
vert2 (weight of vert0 = 1 - u - v) which can be used to
interpolate normals and texture coordinates. Two versions, one for
two-sided triangle casts and one including backface
culling. Algorithm from Moller, Trumbore, "Fast, Minimum Storage
Ray / Triangle Intersection", Journal of Graphics Tools, Volume 2,
Number 1, 1997, pp. 21-28. */
public class RayTriangleIntersection {
private Vec3f edge1 = new Vec3f();
private Vec3f edge2 = new Vec3f();
private Vec3f tvec = new Vec3f();
private Vec3f pvec = new Vec3f();
private Vec3f qvec = new Vec3f();
private static final float EPSILON = 0.000001f;
public boolean intersectTriangle(Line ray,
Vec3f vert0,
Vec3f vert1,
Vec3f vert2,
Vec3f tuv) {
// Find vectors for two edges sharing vert0
edge1.sub(vert1, vert0);
edge2.sub(vert2, vert0);
// Begin calculating determinant -- also used to calculate U parameter
pvec.cross(ray.getDirection(), edge2);
// If determinant is near zero, ray lies in plane of triangle
float det = edge1.dot(pvec);
if (det > -EPSILON && det < EPSILON)
return false;
float invDet = 1.0f / det;
// Calculate distance from vert0 to ray origin
tvec.sub(ray.getPoint(), vert0);
// Calculate U parameter and test bounds
float u = tvec.dot(pvec) * invDet;
if (u < 0.0f || u > 1.0f)
return false;
// Prepare to test V parameter
qvec.cross(tvec, edge1);
// Calculate V parameter and test bounds
float v = ray.getDirection().dot(qvec) * invDet;
if (v < 0.0f || (u + v) > 1.0f)
return false;
// Calculate t, ray intersects triangle
float t = edge2.dot(qvec) * invDet;
tuv.set(t, u, v);
return true;
}
public boolean intersectTriangleBackfaceCulling(Line ray,
Vec3f vert0,
Vec3f vert1,
Vec3f vert2,
Vec3f tuv) {
// Find vectors for two edges sharing vert0
edge1.sub(vert1, vert0);
edge2.sub(vert2, vert0);
// Begin calculating determinant -- also used to calculate U parameter
pvec.cross(ray.getDirection(), edge2);
// If determinant is near zero, ray lies in plane of triangle
float det = edge1.dot(pvec);
if (det < EPSILON)
return false;
// Calculate distance from vert0 to ray origin
tvec.sub(ray.getPoint(), vert0);
// Calculate U parameter and test bounds
float u = tvec.dot(pvec);
if (u < 0.0f || u > det)
return false;
// Prepare to test V parameter
qvec.cross(tvec, edge1);
// Calculate V parameter and test bounds
float v = ray.getDirection().dot(qvec);
if (v < 0.0f || (u + v) > det)
return false;
// Calculate t, scale parameters, ray intersects triangle
float t = edge2.dot(qvec);
float invDet = 1.0f / det;
t *= invDet;
u *= invDet;
v *= invDet;
tuv.set(t, u, v);
return true;
}
}
|
